The present invention relates to a liquid filling method capable of filling liquid such as juice, milk and the like into containers at a rate of as high as 3500 container/nozzlexc2x7hour (2-pitch feed), and a high-speed liquid filling machine used in said method.
Hitherto, a high-speed liquid filling machine provided with a filling station as shown in FIG. 1, for example, has been known as a high-speed liquid filling machine for filling liquid such as milk, juice and the like into paper containers. Said high-speed liquid filling machine is provided with a machine frame 1 which has a filling station, a carrying conveyor 2 capable of carrying a container such that it is sequentially stopped at the filling station, a rotative body 4 having a radial mandrel 3 which is disposed upward of the starting end of the carrying route of said carrying conveyor 2, a filling apparatus 8 having a filling tank 5, a quantifying cylinder 6 and a filling nozzle 7 and a container raising-lowering apparatus 9 which are disposed at the filling station in the midpoint of the carrying route, a heat-sealer 10 disposed at the latter half of the carrying route, and the like.
The filling and packing by using the high-speed liquid filling machine mentioned above comprises the steps of: first, a container material (carton blank) is retrieved while spreading into a tetragonal cylinder shape from a magazine 11 which retains a container material capable of forming into a tetragonal cylinder shape and is sequentially inserted to a mandrel 3, then the end portion which is to become the bottom of the container is heated by a bottom heating apparatus 12, the end portion around the container which had been heated is evenly interfolded by a container end portion interfolding apparatus 13, the aforementioned end portion which had been evenly interfolded is pressed and made to a tetragonal cylinder shaped container with a bottom by a container bottom pressing apparatus 14, and said tetragonal cylinder shaped container with a bottom is transferred from the mandrel to a container holder attached to a chain 15. The aforementioned carrying conveyor 2 is comprised of a chain 15 that is linked with said multiple container holders and a pair of sprockets 16 and 17 that is each provided at the starting end and finishing end of the carrying route which the chain 15 is bridged.
The tetragonal cylinder shaped container with a bottom, which had been transferred to the carrying conveyor, is intermittently carried above a rail 18 that takes and guides the bottom of the container by the container holder attached to chain 15. Said container reaches the filling station via a preparatory interfolding apparatus 19 that puts a crease so that the top portion of the tetragonal cylinder shaped container with a bottom can easily be interfolded into a roof-shape, and a sterilizing apparatus 20 that sterilizes the interior of the container by spraying hydrogen peroxide solution and/or ultraviolet irradiation. After the tetragonal cylinder shaped container with a bottom which is intermittently carried and stops at the filling station is pushed up by the container raising-lowering apparatus 9 and reaches the upper dead point, the filling of liquid from the filling nozzle 7 is started. The filling while lowering continues until the tip of the filling nozzle 7 comes off from the container by the lowering of the container, and carrying of the container is started almost at the same time as the completion of the filling. The tetragonal cylinder shaped container with a bottom in which liquid had been filled passes through a main interfolding apparatus 21 that eventually interfolds the top portion of the container which a crease had been put to a roof-shape, and through a container top portion heating apparatus 22 that heats the sealed surface of the top portion of the container which had been interfolded, and the top portion of the container is heat-sealed by a heat-sealer 10 that presses the top portion of the container, followed by printing of the date or the like by a printing apparatus 23, and is discharged as a product of a package filled with liquid.
To date, in a filling method of liquid such as milk, juice or the like into paper containers that had been carried by an intermittently driving conveyor and stops sequentially at the filling station by using the aforementioned high-speed liquid filling apparatus, a method had been adopted wherein filling is started from the filling nozzle where its tip is adjacent to the bottom of the container, at the time the container is pushed up by the container raising-lowering apparatus and reaches the upper dead point, and filling is conducted while lowering the container so that the liquid filled does not contact the tip of the tip of the filling nozzle, in order to prevent foaming, spattering and shaking of the liquid. Further, the maximum flow rate of the filling could be reduced in order to prevent foaming, spattering, and shaking of liquid effectively, which occur when filling liquid into a paper container. Since it is necessary to make the fill time as long as possible in order to reduce the maximum flow rate of the filling when the filling amount is constant, filling was continued also when the tip of the filling nozzle is withdrawn from the container in the above-mentioned conventional manner of filling only during the lowering of the container. In such case, the distance between the tip of the nozzle and the fill level became large, causing problems such as foaming of the liquid, and the sealed surface which is heat-sealed after the filling being contaminated due to spattering of the liquid.
Further, as a result of extending the fill time, the timing for draining in the filling nozzle became slow, and the liquid was adhered to the sealed surface, and the liquid surface immediately after the filling became unstable, causing a problem which had a bad effect on high-speed filling due to the shaking of liquid or the like when carrying. In addition, since the filling at the point it reaches the upper dead point starts where the container is empty, the distance between the tip portion of the nozzle and the bottom of the container is set to an adjacent distance of 5 to 10 mm in view of the spattering and foaming, and therefore, the filling amount near the upper dead point cannot be increased. Therefore, the maximum flow rate for filling had to be increased in order for the filling to be conducted within a given period of time, which often caused foaming, spattering, and shaking of liquid. Extending the fill time can be considered in order to improve said situation of filling. However, in that case, the time for lowering the container becomes long, causing the time the intermittently carrying conveyor is stopped to become longer, inevitably making the transport time of the conveyor shortened when speed up is planned. Consequently, the shaking of liquid becomes harder as the acceleration flow rate when transporting increases, and there was a concern that the sealed surface would be contaminated and cause seal defection.
Planning of the speed up of machine is concerned in order to improve the filling capability in a filling machine. The more the speed up is planned, the more the operation cycle of the machine becomes shorter, thereby making the fill time required for one container shorter, and liquid corresponding to the inside capacity of the container is filled within a limited time of about one second, and is necessary to carry to the next process. In order to do so, the discharge flow rate during the filling has to be increased, however, increasing the flow rate generates foaming, spattering, and shaking of liquid. The filling capability is determined according to the generation of said foaming, spattering, and shaking of liquid, and to date, it could not exceed 3000 containers/nozzlexc2x7hour (2-pitch feed). An object of the present invention is to provide a liquid filling method capable of filling liquid at a rate of as high as 3500 containers/nozzlexc2x7hour (2-pitch feed) without causing problems such as foaming and turbulence of liquid surface inside the containers and a high-speed liquid filling machine used in said method.
The inventors of the present invention have conducted an intensive study to elucidate the object mentioned above, and have discovered that high-speed filling can be conducted by the following: filling is started when the container is raised before it reaches the upper dead point of raising and lowering, the distance between the tip portion of the nozzle and the bottom of the container is made greater, the container is filled with a specified amount of liquid at the upper dead point of raising and lowering, and then filling is continued while lowering the container. The inventors also discovered that without having to increase the filling flow rate, and, particularly by finishing the filling before withdrawal of the nozzle from the container when filling into a container having a head space, the generation of foaming, spattering, and shaking of liquid can be suppressed. Thus, the present invention had been completed.
More specifically, the present invention relates to a liquid filling method wherein said method is a method of filling liquid into a container while raising and lowering said container, where filling is started when the container is raised before it reaches an upper dead point of raising and lowering, the container is filled with a specified amount of liquid at the upper dead point of raising and lowering, and then filling is continued while lowering the container (claim 1), the liquid filling method according to claim 1, wherein a container is intermittently carried sequentially to a filling station (claim 2), the liquid filling method according to claim 1 or 2, wherein filling is continued from the start of the filling to the end of the filling (claim 3), the liquid filling method according to any of claims 1 to 3, wherein the start of filling is advanced 1xc2x0 to 90xc2x0 from an upper dead point of raising and lowering in one raising and lowering cycle of 360xc2x0 (claim 4), the liquid filling method according to any of claims 1 to 4, wherein the distance between a tip of a filling nozzle and a bottom of a container is 20 mm to 70 mm in an upper dead point of raising and lowering (claim 5), the liquid filling method according to any of claims 1 to 5, wherein the distance between a liquid surface inside a container and a tip portion of a nozzle is 1 mm to 15 mm when filling in the lowering movement (claim 6), the liquid filling method according to any of claims 2 to 6, wherein filling is started before the carrying of a container is stopped (claim 7), the liquid filling method according to any of claims 2 to 7, wherein the start of raising a container is advanced 20xc2x0 to 50xc2x0 from the stopping of carrying in one carrying cycle of 360xc2x0 (claim 8), the liquid filling method according to any of claims 2 to 8, wherein carrying is started before the lowering of a container is finished (claim 9), the liquid filling method according to any of claims 2 to 9, wherein the start of carrying of a container is advanced 40xc2x0 to 70xc2x0 from the end of lowering in one raising and lowering cycle of 360xc2x0 (claim 10).
Moreover, the present invention relates to a high-speed liquid filling machine wherein said machine is provided with a carrying conveyor capable of carrying a container such that it stops sequentially at a filling station and a filling apparatus and a container raising-lowering apparatus disposed in the filling station, where said machine is provided with a controlling means capable of controlling such that filling is started when the container is raised before it reaches the upper dead point of raising and lowering, the container is filled with a specified amount of liquid at the upper dead point of raising and lowering, and then filling is continued while lowering the container (claim 11), the high-speed liquid filling machine according to claim 11, wherein the filling apparatus is provided with a filling nozzle disposed upward to the carrying route of a container, a quantifying cylinder which has a built-in piston and sends liquid to a filling nozzle by reciprocation of said piston, and an independent driving mechanism which reciprocates said piston at a random amount of stroke and/or a random speed of stroke (claim 12), the high-speed liquid filling machine according to claims 11 or 12, wherein the controlling means is capable of controlling such that filling is continued from the start of the filling to the end of the filling (claim 13), the high-speed liquid filling machine according to any of claims 11 to 13, wherein the controlling means is capable of controlling such that the start of the filling is advanced 1xc2x0 to 90xc2x0 from an upper dead point of raising and lowering in one raising and lowering cycle of 360xc2x0 (claim 14), the high-speed liquid filling machine according to any of claims 11 to 14, wherein the controlling means is capable of controlling such that the distance between a tip of a filling nozzle and a bottom of a container is 20 mm to 70 mm in an upper dead point of raising and lowering (claim 15), the high-speed liquid filling machine according to any of claims 11 to 15, wherein the controlling means is capable of controlling such that the distance between a liquid surface inside the container and a tip portion of the nozzle is 1 mm to 15 mm when filling in the lowering movement (claim 16), the high-speed liquid filling machine according to any of claims 11 to 16, wherein the controlling means is a means capable of controlling such that filling is started before the carrying of a container is stopped (claim 17)., the high-speed liquid filling machine according to any of claims 11 to 17, wherein the controlling means is a means capable of controlling such that the start of raising a container is advanced 20xc2x0 to 50xc2x0 from the stopping of carrying in one carrying cycle of 360xc2x0 (claim 18), the high-speed liquid filling machine according to any of claims 11 to 18, wherein the controlling means is a means capable of controlling such that the carrying is started before the lowering of a container is finished (claim 19), the high-speed liquid filling machine according to any of claims 11 to 19, wherein the controlling means is a means capable of controlling such that the start of carrying the container is advanced 40xc2x0 to 70xc2x0 from the end of lowering in one raising and lowering cycle of 360xc2x0 (claim 20), and the high-speed liquid filling machine according to any of claims 11 to 20, wherein the control by the controlling means is conducted by changing the setting pulse of a servomotor (claim 21).